This project focuses upon C.A.S.A. (computer aided sperm analysis) technology for analysis of sperm motion. In the Phase II project, the technological accomplishments of the prototype system tested in Phase I will, with certain innovations, be upgraded into a clinical instrument (Specific Aim 1) which will be validated (Specific Aim 2) and clinically tested (Specific Aim 3). Innovations for Phase II include: a method for optimization of phase contrast optics for human sperm, addition of strobed fluorescent capability to the internal optical system developed in Phase I, and rapid electronic alternation of strobed fluorescent and phase contrast illuminations. Software for this system will have the flexibility to produce data consistent with evolving W.H.O. and C.A.P. guidelines. The instrument will substantially increase both the range of tests accessible to automated semen analysis and the corresponding commercial opportunities for the end product.